San Francisco, CA USA (UroToday.com) Radium-223 is approved for symptomatic bone metastasis in castrate-resistant prostate cancer and is shown to improve patient overall survival. A course of Radium-223 is an injection every 4 weeks for total 6 doses. Treatment beyond that is yet unknown and remains the subject of this international propective study.
Patients with CRPC with ≥ 2 bone metastasis who completed 6 dose initial Ra-223 injection with no disease progression in bone who progressed after initial treatment were eligible for Ra-223 retreatment. Primary objective was safety. Secondary objectives include time to radiographic bone progression, time to ALP progression, and radiographic progression-free survival (rPFS) based on MRI/CT or bone scans performed every 3 months.
44 patients underwent Ra-223 retreatment with demographics similar to prior ALSYMPCA study, which led to initial approval of Ra-223. 66% patients completed the entire retreatment course of all 6 injections. No new safety concerns were noted. Incidence of adverse events was again comparable to ALSYMPCA study. Most common hematologic Gr 3/4 adverse event remains anemia. Only 1 patient had radiographic bone progression. Median time to ALP progression was not reached. Median time to radiographic PFS was 9.9 months. Of 13 patients with progression, only 1 had bone progression.
The group concludes that Ra-223 retreatment is well tolerated and can be efficacious clinically as seen with rare bone metastases progression. An ongoing study NCT02023697 is addressing expanded ra-223 dosing and treatment duration.
Reported by:
Mohammed Haseebuddin, MD at the 2016 Genitourinary Cancers Symposium - January 7 - 9, 2016 – San Francisco, CA
Fox Chase Cancer Center, Philadelphia, PA